The invention relates to compositions, methods, and apparatuses for improving a dust control product that over time exhibits residual dust control capabilities. The invention discloses a composition and a method for application of the product onto a surface to provide dust control and further allows for residual dust control after the curing process. The invention not only demonstrates initial and residual dust control it additionally limits moisture re-absorption during storage and transport.
Dust suppression is the reduction of the extent to which finely divided solid particulate material becomes suspended in the air. A variety of materials such as coal, sulfur, phosphate, clay, potash and other finely divided ores and minerals, generate dust in transfer and handling operations during mining, transportation, storage, and use.
Dust is a particularly severe safety and health hazard in coal mining, handling, and storage operations. Coal often chips into small fragments by the action of wind and rain, frictional movement due to motion in transit, and abrasion in handling. Respirable coal dust has a particle size of less than about 10 microns and its inhalation can lead to pneumoconiosis, i.e., “black lung disease”. Also, dust explosions due to spontaneous combustion may occur when the dust is confined to a small air space such as in coal mining operations.
It is known to suppress dust in mines by spraying with various aqueous systems containing chemical additives to improve working conditions and reduce the toxicological risks and explosion hazards. For example, U.S. Pat. No. 4,425,252 describes a method to abate coal dust using an anionic surfactant, preferably sodium dodecylbenzene sulphonate and a nonionic surfactant, preferably a polyethoxylated nonylphenol, in an aqueous formulation. The method comprises spraying the coal dust area with a formulation comprising water containing up to 0.1% by weight of the mixture of the anionic surfactant, i.e., a water soluble salt of an alkyl aryl sulfonic acid and nonionic surfactant having an HLB of from 10 to 16. Optimally, the mixture contains one or more cosolvents generally of the class of alkylene glycol monoalkyl ethers, C2 to C5 alkanols and mixtures thereof.
Furthermore, several techniques have been developed utilizing foamable compositions for suppressing coal dust. For example, U.S. Pat. No. 4,551,261 describes a foam comprising water, a foaming agent, and an elastomeric water insoluble polymer. A variety of anionic and nonionic surfactants and detergent wetting agents are described as useful foaming agents, and a variety of elastomeric and water insoluble synthetic organic polymer binders are described as useful elastomeric water insoluble polymers.
U.S. Pat. No. 4,971,720 relates to a method for suppressing dust process emissions. The method utilizes a foaming agent which may be a low salt tolerant surfactant selected from salts of fatty acids, alkyl sulphates, and alkyl aryl sulphonates. U.S. Pat. No. 4,561,905 describes a coal dust suppression mixture of oil, water and a surfactant in the form of an emulsion that is diluted and foamed. The foam is then sprayed into a falling mass of coal. The oils suitable for use are described as heavy process oils and include asphalt dissolved in a moderately heavy oil, residual flush oils or relatively high viscosity fuel oil. The preferred oils have a viscosity in the range of from approximately 600 to 7,000 SUS at 38° C., a pour point in the range of approximately −18° to 21° C., a molecular weight of at least 300 and a boiling point of at least 204° C. U.S. Pat. No. 4,944,892 teaches an aqueous composition which comprises a linear primary alcohol ethoxylate surfactant, a suitable scenting oil such as pine oil or lemon oil and water among other adjuvants. U.S. Pat. No. 4,929,278 discloses an aqueous bath preparation which comprises essential oils such as orange peel oil, orange oil, lemon oil or the like. Further, the bath preparation comprises a soap or surfactant which may include straight chain alkyl benzenesulfonates, alkyl sulfuric acid ester, alkyl ether sulfuric acid ester and the like. U.S. Pat. No. No. 3,367,878 shows a composition which comprises 20.2% by weight water, 1.0% by weight pine oil, 1.8% by weight sodium xylene sulphonate surfactant. U.S. Pat. No. 4,175,062 teaches an aqueous composition which comprises 7.5% by weight of sodium dodecylhenzene sulfonate, 0.8% by weight of pine oil and other adjuvants. Japanese Patent 44,495 discloses an aqueous composition which comprises 20% by weight of sodium lauryl benzene sulfonate and 1% by weight of D-limonene along with other adjuvants.
Thus, various techniques have been developed to suppress and control dust especially in the mining of minerals, and many of the techniques are effective for reducing dust. However, there is still a need for improvement in dust suppression. In relation to finely divided ores and mineral mining many of the prior techniques were developed without a need to address problems associated with modern mining practices.
The art described in this section is not intended to constitute an admission that any patent, publication or other information referred to herein is “prior art” with respect to this invention, unless specifically designated as such. In addition, this section should not be construed to mean that a search has been made or that no other pertinent information as defined in 37 CFR §1.56(a) exists.